How We Reduced API Response Times by 70% with Redis Caching

One of our clients was experiencing 800ms+ API response times under moderate load. By introducing Redis caching at the right layers — query results, aggregations, and computed data — we brought average response times down to under 250ms. This post covers our exact caching strategy: what to cache, for how long, how to invalidate intelligently, and how to avoid cache stampedes. We also discuss the trade-offs between cache-aside, write-through, and write-behind patterns.